Filling or root canal? When a filling is enough
In short: it depends on how far the cavity has gone. If it doesn’t touch the nerve, a filling fixes it. If the nerve is already affected or infected, you need a root canal. It’s not something you choose: the depth of the damage decides. And the moral is always the same: the sooner, the easier (and cheaper).
What is each one?
- Filling: the cavity is cleaned and the hole is filled with a tooth-coloured material. Quick and simple, as long as the nerve is healthy.
- Root canal: when the nerve is damaged or infected, it’s removed, the inside of the tooth is cleaned and sealed. It saves the tooth, but it’s more treatment.
What decides one or the other?
The depth. A small or medium cavity, far from the nerve, gets a filling. A deep cavity that reaches the nerve (or a tooth whose nerve is already infected) needs a root canal. The dentist assesses it by looking at the tooth and, very often, with an X-ray that shows what you can’t see with the naked eye.
Signs that a filling might no longer be enough
- Pain that comes on its own, throbs or wakes you at night.
- A lot of sensitivity to cold or heat that lasts a good while.
- The tooth hurts when biting or has darkened.
It doesn’t always hurt, mind: some nerves get infected silently. That’s why a check-up catches cavities while they’re still just a filling.
And if it’s not treated?
A cavity doesn’t stop on its own: left alone, it reaches the nerve (root canal) and, if still left, can end in extraction. Each stage you skip in time is treatment you save.
Got a cavity or a tooth that’s bothering you and don’t know “how bad it is”? Come in and we’ll tell you clearly, with a fixed quote. The first visit is free: book an appointment.
Frequently asked questions
What's the difference between a filling and a root canal?
A filling cleans the cavity and fills the hole when the damage hasn't reached the nerve. A root canal is done when the nerve is already affected or infected: the damaged nerve is removed, the inside of the tooth is cleaned and sealed. The deeper it goes, the more treatment.
Can I choose a filling instead of a root canal?
It's not about choosing, but about how far the damage has gone. If the nerve is healthy, a filling is enough; if it's affected, a filling solves nothing (it would still hurt or get infected). It's decided by the examination and sometimes an X-ray.
Why does what was going to be a filling sometimes end up as a root canal?
Because until the cavity is cleaned out you can't fully see how deep it is. If cleaning it reaches the nerve, what looked like a filling becomes a root canal. That's why going early, when the cavity is small, avoids exactly that.
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